Elevator for fragile, discrete material



March 1, 1966 K. M. ALLEN ETAL ELEVATOR FOR FRAGILE, DISCRETE MATERIALOriginal Filed Sept. 24, 1962 l/Vl/E/VTORS.

KENNETH M. ALLEN CHESTER H. HARPER BUCKHORN, CHEATHAM 8 BLORE ATTORNEYSUnited States Patent 3,237,753 ELEVATGR FGR FRAGILE, DISCRETE MATERIALKenneth M. Allen and Chester H. Harper, Newherg, Greg, assignors toAllen-Harper, lnc., Newherg, Greg, a corporation of Oregon Continuationof application Ser. No. 225,728, Sept. 24, 1962. This application Feb.8, 1965, Ser. N 0. 438,146 4 Claims. (Cl. 198129) This is a continuationof our copending application Serial No. 225,728, filed September 24,1962.

Our present invention comprises an elevator for fragile, discretematerials of flake type such as potato chips, crackers, and the like.The invention is of particular utility in the manufacture of potatochips in which it may be desirable to elevate the potato chips from afloor-level fryer to an overhead conveyor for distributing the chipsinto a battery of floor-level packaging machines. A bucket or brackettype elevating conveyor is very wasteful of such articles since thebuckets or brackets crush many of the chips. As a result elevators ofthe flat belt or screen type have been employed in which the chips intoa battery of floor-level packaging machines. by gravity. Such a conveyormust be extremely'long since the maximum angle of inclination is aroundtwenty degrees, resulting in loss of valuable space and in some casesthe necessity for turntables to bring the potato chips back overhead inthe available plant space.

The present invention comprises means for elevating such articles bymeans of a screen type belt conveyor to which the articles are held bysuction and which may travel at a steep inclination closely approachingninety degrees to the horizontal.

An object of the present invention is to provide a conveyor of theforegoing type in which means are provided to regulate the suction forceholding the material to the screen so as to minimize breakage, adapt themachine to articles of diflerent types, and control the quantity ofmaterial elevated thereby per increment of time so as to regulate thecapacity of the elevator to the capacity of succeeding machines to whichthe material is to be fed.

The objects and advantages of the present invention will be more readilyapparent from inspection of the following specification taken inconnection with the accompanying drawings, wherein like numerals referto like parts throughout, and in which the invention is described andillustrated.

In the drawings,

FIG. 1 is a view in perspective, with parts broken away, illustrating apreferred form of the present invention in association with materialsupplying and material removing conveying means; and

FIG. 2 is a partial side view of a modified form of conveyor supportingroll.

Referring to FIG. 1, the elevator of the present invention isillustrated in association with a material supplying conveyor 12 forfeeding materials to the elevator and a second material conveying means14 for removing materials from the elevator.

The elevator 10 comprises a suction box 16 having an open, upright side18 and an open, horizontal top 20, the remainder of the box comprisingvertical sides 22, 24 and 26 with which may be associated a bottom wall28, which in practice may be provided by the floor of the space uponwhich the elevator rests. An endless screen 30 is mounted on the box insuch manner that a nearly vertical flight 32 thereof spans the open side18 and a succeeding horizontal flight 34 thereof spans the open top 20.The flights 32 and 34 together constitute the feeding flight of thescreen and the return flight of the screen is constituted by a flight 36parallel to the flight 34 and a flight 38 parallel to the flight 32. Thescreen is preferably attached between parallel sprocket chains 40 and 42which are guided by sprockets such as the sprockets 44 and 46. Thelowermost part of the screen is trained around a roll 48 mountedhorizontally within the lower front portion of the suction box andconnected to a driving motor 50.

At the junction of the flights 32 and 34 the feeding flight of thescreen is guided around a skeletal roll 52 comprising a plurality ofthin discs 54 mounted upon a horizontal shaft 56. The screen is thenguided around a solid roll 58 at the end of the horizontal flight 34. Atthe junction of return flight portions 36 and 33 the screen is guidedaround a suitable roll (not shown), mounted upon a shaft 60.

The vertical wall 24 is provided with a plurality of air outlet openings62 in each of which there is mounted a motor driven propeller 64 drivenin such direction as to exhaust air from the box and create a negativepressure therein. Air is drawn into the box through the feeding andreturn flights of the screen. The flow of air is relatively unimpeded bythe skeletal roll, but is blocked by the solid roll 58.

The feeding conveyor 12 drops the material into a chute 66 having aninclined bottom wall 68 terminating closely adjacent the lower portionof the upwardly moving feeding flight 32. The chips or other materialsare thereby delivered into such proximity to the feeding flight of thescreen that they may be picked up and held in a layer against the outersurface of the screen. The holding force will continue while the screenpasses around the skeletal roll 52 but will be discontinued when thescreen passes around the solid roll 58 in order that the material may bereleased to drop into the removing conveyor 14.

Situated beneath the horizontal return flight 36 is an adjusting vane 70pivotally mounted on a shaft 72 adjacent and beneath the solid roll 58.A slotted arcuate arm 74 is affixed to the shaft '72 and a wing nutclamping de vice 76 is provided to hold the vane 70 in the desiredposition. The vane provides a gradual reduction of flow of air throughthe upper horizontal flight 34 of the conveyor as the solid roll 58 isapproached. If such vane is omitted or moved to a position which is toolow, there is an abrupt change in air flow through the flight 34 from arelatively high rate to substantially zero rate immediately adjacent theroll 58. The result is that air entering the top of the flightimmediately adjacent the roll 58 has relatively high velocity over thetop of the roll in a direction opposite the direction of movement of theflight 34. This causes particles of light weight materials to be heldfrom movement with the conveyor. The result is a piling up of suchmaterials on the flight 34 adjacent the roll 58 and then the dischargeof large bunches of such material over the roll 58. By adjusting theposition of the vane 70 the negative pressure applied to the upperflight 34 and therefore the amount of air drawn through the upper flightcan be reduced to a desired value. Also, the negative pressure and theamount of such air gradually decreases along the flight as the dischargeportion of the flight is approached so that the tendency for lightmaterial to pile up on the flight is largely eliminated.

The same type of problem at the upper end of the vertical or steeplyinclined flight 32 is encountered if the horizontal flight 34 isomitted. It is extremely diflicult on such a vertical or steeplyinclined flight to gradually reduce the negative pressure adjacent theupper end of such flight so that particles or flakes of light materialare carried over the upper roll without being forced rearwardly anddislodged from the flight so that they fall downwardly. The gradualreduction of negative pressure can, however, be accomplished on ahorizontal flight as explained above, and it will be apparent that suchflight need not be exactly horizontal but that it may also be inclinedso long as its inclination is substantially less than that of thesteeply inclined flight and such that the particles or flakes will notslide downwardly thereon when the negative pressure applied to suchflight approaches zero.

If the material being conveyed contains substantial moisture or othervolatile liquid, it will be apparent that the negative pressure appliedto such material in conjunction with the rapid movement of air past theparticles of such material will produce a rapid drying action. This willresult in rapid cooling of heated materials containing volatiles. Forexample, freshly cooked potato chips contain substantial moisture andare in a heated condition and can be rapidly cooled and dried whilebeing elevated to the input of packaging machines. Also, flakes or otherparticles of cereal products which have been sprayed with a sugarsolution can be rapidly dried and, if desired, heated air or other gascan be directed toward the material on the conveyor so as to be drawnthrough such material by the negative pressure in the interior of thesuction box 16.

A different form of skeletal roll which may be substituted for the roll52 is illustrated in FIG. 2 as comprising a hollow cylinder 80 having aplurality of closely spaced slots 82 therein. It is apparent that othertypes of skeletal rolls may be utilized, and it is also apparent that itmay de desirable, in some instances, to position the vane 70 between theconveyor flights 34 and 36.

The conveying means 12 and 14 herein illustrated may be such asdisclosed and claimed in our prior Patent No. 2,899,044, issued August11, 1959, or may be any other suitable type of conveying means.

Having illustrated and described a preferred embodiment of theinvention, it should be apparent to those skilled in the art that theinvention permits of modification in arrangement and detail. We claim asour invention all such modifications as come within the true spirit andscope of the following claims.

What is claimed is:

1. An elevator for fragile, discrete materials comprising:

(a) a suction box having an open upright side and an open top,

(b) an endless screen having a steeply inclined flight spanning saidopen upright side and a succeeding substantially horizontal secondflight spanning said open top and having a discharge portion,

() means for supporting said endless screen including a skeletal roll atthe junction of said inclined and horizontal flights,

(d) means for driving said screen,

(e) means including a chute terminating adjacent the outer surface ofsaid inclined flight for delivering materials to said elevator,

(f) means for creating negative air pressure associated with saidsuction box suflicient to hold materials of the above-mentioned type tothe outer surface of said inclined flight,

(g) and means within said suction box for varying the negative airpressure applied to said second substantially horizontal flight as saiddischarge portion is approached, comprising 'a pivoted vane positionedbeneath said second flight and adjustably movable to variousinclinations Within said suction box.

2. In an elevator for fragile, discrete materials,

a suction box having an open upright side and an open an endless screenhaving a steeply inclined flight spanning said open upright side and asucceeding substantially horizontal second flight spanning said open topand having a discharge portion,

guide means for supporting said endless screen at the junction of saidinclined and horizontal flights,

means for driving said screen, means for delivering materials to saidinclined flight, means for creating negative air pressure in saidsuction box suflicient to hold materials of the above-mentioned type tothe outer surface of said inclined flight, and means within said suctionbox for gradually reducing the negative air pressure applied to saidsecond substantially horizontal flight as said discharge portion isapproached. 3. In an elevator for fragile, discrete materials, anendless screen, means for guiding the endless screen in a steeplyinclined flight upwardly to a succeeding substantially horizontal flightto a discharge point and along re turn flights to the bottom end of thesteeply inclined flight and forming no substantial impediment to flow ofair through any of the portions of the screen in the inclined flight andthe horizontal flight, means for driving the screen upwardly along thesteeply inclined flight and from the inclined flight along thehorizontal flight to the return flights and forming no substantialimpediment to flow of air through any of the portions of the screenextending along the inclined flight and the horizontal flight, a suctionbox having an opening extending continuously along the inclined flightand the horizontal flight, means for creating negative air pressure inthe suction box of a predetermined magnitude suflicient to hold fragile,discrete particles on the portion of the screen traveling up theinclined flight and on the horizontal flight, and air-direction meansfor gradually reducing the magnitude of the negative air pressureapplied to the horizontal flight proceeding toward the discharge pointto a magnitude substantially lower than said predetermined magnitude atthe discharge point. 4. In an elevator for fragile, discrete materials,an endless screen, means for guiding the endless screen in a steeplyinclined flight upwardly to a succeeding substantially horizontal flightand along return flights to the bottom end of the steeply inclinedflight and forming no substantial impediment to flow of air through anyof the portions of the screen in the inclined flight and the portion ofthe horizontal flight adjacent the inclined flight, means for advancingthe screen upwardly along the steeply inclined flight and from theinclined flight along the horizontal flight to the return flights andformin no substantial impediment to flow of air through any of theportions of the screen extending along the inclined flight and theportion of the horizontal flight adjacent the inclined flight, means forforcing air downwardly through the inclined flight and the portion ofthe horizontal flight adjacent thereto to press fragile, discreteparticles against the portions of the screen in the upwardly inclinedflight and the portion of the horizontal flight adjacent thereto, andmeans for gradually reducing the magnitude of flow of the air from apredetermined magnitude at the junction of the inclined flight and thehorizontal flight to a substantially lesser magnitude at a point on thehorizontal flight spaced substantially from the junction of the inclinedflight and the horizontal flight.

References Cited by the Examiner v UNITED STATES PATENTS 1,377,1365/1921 Lawrence et al 214-309 3,086,253 4/1963 .loa 19-1563 X SAMUEL F.COLEMAN, Primary Examiner.

1. AN ELEVATOR FOR FRAGILE, DISCRETE MATERIALS COMPRISING: (A) A SUCTIONBOX HAVING AN OPEN UPRIGHT SIDE AND AN OPEN TOP, (B) AN ENDLESS SCREENHAVING A STEEPLY INCLINED FLIGHT SPANNING SAID OPEN UPRIGHT SIDE AND ASUCCEEDING SUBSTANTIALLY HORIZONTAL SECOND FLIGHT SPANNING SAID OPEN TOAND HAVING A DISCHARGE PORTION, (C) MEANS FOR SUPPORTING SAID ENDLESSSCREEN INCLUDING A SKELETAL ROLL AT THE JUNCTION OF SAID INCLINED ANDHORIZONTAL FLIGHTS, (D) MEANS FOR DRIVING SAID SCREEN, (E) MEANSINCLUDING A CHUTE TERMINATING ADJACENT THE OUTER SURFACE OF SAIDINCLINED FLIGHT FOR DELIVERING MATERIALS TO SAID ELEVATOR, (F) MEANS FORCREATING NEGATIVE AIR PRESSURE ASSOCIATED WITH SAID SUCTION BOXSUFFICIENT TO HOLD MATERIALS OF THE ABOVE-MENTIONED TYPE TO THE OUTERSURFACE OF SAID INCLINED FLIGHT, (G) AND MEANS WITHIN SAID SUCTION BOXFOR VARYING THE NEGATIVE AIR PRESSURE APPLIED TO SAID SECONDSUBSTANTIALLY HORIZONTAL FLIGHT AS SAID DISCHARGE PORTION IS APPROACHED,COMPRISING A PIVOTED VANE POSITIONED BENEATH SAID SECOND FLIGHT ANDADJUSTABLY MOVABLE TO VARIOUS INCLINATIONS WITHIN SAID SUCTION BOX.